Inside the science behind new HIV/Aids treatments

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Revision of the international guidelines on treatment for HIV/Aids could avoid an estimated 21 million Aids deaths by 2030, says the UN Aidss agency and World Health Organisation (WHO). The recent amendments would see treatment offered as soon as someone learns they are infected with the virus – as opposed to waiting until they become sick. Over the past 30 years, treatment for the condition has been revolutionised; a HIV positive test result is no longer the near-death sentence it once was. Despite this, the global burden of the epidemic remains high: 1.5 million people died of Aids related illnesses in 2013.

At present, HIV positive individuals are tested regularly to monitor the effects of the virus on their immune system. Progression of the disease is measured using the number of CD4+ lymphocytes, a white blood cell that helps to initiate the immune response upon detection of ‘foreign’ microbes in the body. Treatment, which involves a combination of medicines – the virus can quickly become resistant to one single drug – is traditionally only offered when a person’s CD4+ count drops below 350.

New strategies involve offering Anti-Retroviral Therapy to every person diagnosed with HIV, regardless of their CD4+ count. Alongside this, individuals at high risk of infection should be offered preventative medication. This model is currently being implemented in San Francisco, once considered ‘ground zero’ of the HIV epidemic, with great success. In 2014, only 177 citizens died of HIV, a radical drop from 1,641 in 1992. Furthermore, viral suppression – the point at which a person with HIV is no longer infectious to others- is dramatically higher in San Francisco: 72 per cent of patients take their medication regularly, compared to a less favourable 30 per cent across the rest of America. Evidently, the new system has the potential to work well in situ.

The large-scale clinical trial, on which these recommendations were founded, proved to be so efficacious that it was halted one year early. Providing immediate treatment meant that people were 53 per cent less likely to develop Aids or die during the course of the study. As summarised by Dr Anthony S Fauci, director of the National Institute for Allergy and Infectious Disease in America, “the sooner, the better” should be the motto for treatment. It is hoped that upheaval of the current guidelines might encourage at-risk individuals to get tested earlier. The ‘Test and Treat’ methodology employed in San Francisco, where a person is given medication as soon as they test positive, has already achieved great change since its implementation in 2010. While taking Anti-Retrovirals, patients are far less likely to die of HIV related illness and are also less likely to infect others through unprotected sex. A win-win for all involved.

A large part of alleviating the HIV epidemic has been rooted in education. This is predominantly about the risk of infection, but also to reduce endemic stigma surrounding the disease that was once considered a ‘gay plague’. However, concerns remain that the real barrier to change is not prejudice, but funding. The strategy works in San Francisco, but this is in part due to a demographic of more affluent, white gay males, who are more likely to know the risks and be insured, and political candidates who support the Aids budget. To contend with the world burden of Aids would be a much more complex undertaking. Treating every HIV positive person in a middle or low income country would cost around $20 billion a year (around triple the present US annual expenditure). Whether this is financially viable or not remains to be seen.

It is worth remembering, that despite progress in the developed world, the international burden of Aids remains heavy. Certainly new guidelines for treatment alone will not solve the global problem of HIV and Aids, but as demonstrated in the case of San Francisco, they are undoubtedly a step in the right direction.